Basically in a nutshell, any attempt to disable prefixes or xpaths that in fact are attributes and not nodes, yields either no results at all (disable prefixes) or a DOMDocument error (disable xpaths). The prefixes problem is because the 'attribute' prefixes are not run through the 'disabled prefixes' list. The disable xpaths problem, will take a little investigation to track down the exact problem and how to solve it.